Biology

Cell Cycle and Chromosomes

1,219 Questions

Explore a curated list of questions covering the cell cycle, mitosis, and meiosis. Topics include DNA replication, chromosomal structures, and genetic disorders. This material is essential for students preparing for biology and general science competitive exams.

Cell cycle eventsDNA replicationMeiosis processChromosomal structuresGenetic disorders

Cell Cycle and Chromosomes Questions

Multiple choice biology cell-the basic unit of life nucleus organelles in cell membranous and non-membranous organells

The mature mammalian red blood cells are incapable of further division because

  1. DNA sequences are redundant

  2. The nuclei are lobed

  3. They lack nuclei

  4. The mitotic apparatus is absent
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Because of the lack of nuclei and organelles, mature red blood cells do not contain DNA and cannot synthesize any RNA, and consequently can not divide and have limited repair capabilities. 

So, the correct option is C. (They lack nuclei)

Multiple choice biology cell-the basic unit of life nucleus organelles in cell membranous and non-membranous organells

Number of chromosomes in nucellus is 24. Number of chromosomes in aleurone be.

  1. 30

  2. 24

  3. 36

  4. 19
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The nucellus is diploid (2n), so 2n = 24, which means the haploid number n = 12. The aleurone layer in seeds is triploid (3n) because it results from triple fusion. Thus, the number of chromosomes in the aleurone layer is 3 * 12 = 36.

Multiple choice biology cell-the basic unit of life nucleus organelles in cell membranous and non-membranous organells

The chromosomes lies inside

  1. Nucleus

  2. Nucleolus

  3. Cytoplasm

  4. Golgi apparatus
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The nucleolus is the largest structure present in the nucleus. Ribosome synthesis and assemblage occurs in nucleolus region. 
Chromosomes are not present in the cytoplasm. 
Golgi apparatus does not possess chromosomes. 
The nucleus is the double membrane bound structure of the cell in which most of the genetic material is present in the form of chromosomes. The nucleus is present in eukaryotic cells. Thus, the correct answer is option A.

Multiple choice biology cell-the basic unit of life nucleus organelles in cell membranous and non-membranous organells

Where are the chromosomes found in cell? 

  1. Nucleus

  2. Cytoplasm

  3. Lysosome

  4. Ribosome
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A chromosome is a thread-like structure which is made of DNA tightly coiled many times around protein core made of histone proteins. Histone protein supports and stabilizes the structure. They are found in the nucleoplasm of the nucleus. They are absent in cytoplasm, lysosome, and ribosome. 

Multiple choice biology cell-the basic unit of life nucleus organelles in cell membranous and non-membranous organells

Karyology is the study of

  1. Cytoplasm

  2. Cell

  3. Mitochondria

  4. Nucleus
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
  • A karyotype is the number and appearance of chromosomes in the nucleus of a eukaryotic cell. The term is also used for the complete set of chromosomes in a species or in an individual organism. The study of whole sets of chromosomes is sometimes known as karyology. Hence, the karyology is the study of the nucleus.
  • So, the correct answer is 'nucleus'.
Multiple choice biology cell-the basic unit of life nucleus organelles in cell membranous and non-membranous organells

Experiments to demonstrate importance of nucleus in controlling growth and heredity were performed on

  1. Acetabularia

  2. Neurospora

  3. Leucocytes

  4. Starfish egg
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

  • Hammerling's nucleocytoplasmic experiments state that the cytoplasm is the centre for all the metabolic activities in the cell and the nucleus is the controlling centre. 

  • This experiment was conducted using Acetabularia.

  • Acetabularia is a genus unicellular or single-celled green algae belonging to the family Polyphysaceae which are found in subtropical waters.

  • They are gigantic in size and complex in form, therefore, used in experiments in cell biology.

  • So, the correct answer is 'Acetabularia'.

Multiple choice biology cell-the basic unit of life nucleus organelles in cell membranous and non-membranous organells

Chromatin material which remains condensed during interphase is called

  1. Heterochromatin

  2. Euchromatin

  3. Chromonemata

  4. Megachromatin
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • Chromatin material which remains condensed during interphase is called heterochromatin.
  • Heterochromatin refers to the certain regions of DNA found on the chromosomes of a eukaryotic cell.
  • The heterochromatin gets darkly stained due to the highly condensed nature of the DNA in these regions and has higher ribonucleic acid content.
  • This heterochromatin is made up of high copy number tandem repeats (repetitive nucleotides).
  • So, the correct answer is 'Heterochromatin'.
Multiple choice bio-chemistry applications of biotechnology pcr cutting, insertion and ligation of dna gene cloning procedure biotechnological regulations asexual modes of reproduction

An analysis of chromosomal DNA using Southern hybridisation technique does not use

  1. Blotting

  2. Autoradiography

  3. PCR

  4. Electrophoresis
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Southern hybridization involves DNA digestion, electrophoresis, blotting, and probe hybridization. PCR is a separate technique for amplification and is not a standard step in the Southern blotting procedure itself.

Multiple choice bio-chemistry applications of biotechnology pcr cutting, insertion and ligation of dna gene cloning procedure biotechnological regulations asexual modes of reproduction

Which ones are simple sequence repeats (SSRs)

  1. Minisatellite sequences

  2. Microsatellites

  3. Pseudogenes

  4. Multiple gene family.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Simple sequence repeats (SSRs), sometimes described as genetic 'stutters,' are DNA tracts in which a short base-pair motif is repeated several to many times in tandem (e.g. CAGCAGCAG). These sequences experience frequent mutations that alter the number of repeats similar to Multigene Family, a set of genes descended by duplication and variation from some ancestral gene.

So, the correct answer is 'Multiple gene family.'

Multiple choice botany reproduction in angiospermic plants artificial vegetative propagation common modes of vegetative propagation vegetative propagation asexual modes of reproduction

In a grafted plant, stock has $48$ chromosomes while scion has $24$ chromosomes. The chromosome number for root cells and eggs are.

  1. $48$ and $24$
  2. $24$ and $24$
  3. $24$ and $12$
  4. $48$ and $12$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The stock is the plant part containing strong root system and sicon is the plant part which contains better fruit and fruit yield. In root cells, the chromosome number remains constant, reduced half in egg cell. So the chromosome number for root cells are 48 and eggs are 12.

So the correct option is '48 and 12'.

Multiple choice botany heredity: from parents to offsprings experiments of mendel mendel's law of inheritance works of mendel

Independent assortment is absent in case of

  1. Genes located on the same chromosome

  2. Genes located on homologous chromosomes

  3. Genes located on nonhomologous chromosomes

  4. All of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Independent assortment is segregation of factors for a trait independent of other factors during gamete formation followed by their random rearrangement in progeny thereby producing both parental and new combinations. The linkage is the tendency of closely placed genes on a chromosome to stay together during inheritance; it produces more parental combination and less/no new combinations of the gene. The linkage is indirectly proportional to the distance between genes; the less the distance between the genes, the more linkage frequency between them. Genes present together on a chromosome may show linkage, if they are close enough, and do not follow independent assortment. Genes present on homologous and nonhomologous chromosomes are too far apart from each other to show linkage. The correct answer is A.